[-Richard-]

If you are a "purest" who compares the sound of his/her system to what they believe or imagine the "real thing" sounds like than this information will not interest you. Save yourself any anguish by skipping this thread.

I was talking to a designer yesterday of double-mouth folded-horn single-driver baffles... based on the Fugal-Horn schematics... a very nice guy. He described what the double-mouth design does for the "tone" of a single driver... a most impressive description that I had no doubt works effectively.

After I hung up I let my mind relax as I listened to the music on my OB's: Visaton B200 + Eminence Alpha-15A on a simple flat baffle. I am currently using Vinnie Rossi's Signature 70.2 monoblocks and Lloyd Peppard's Magic 5 triode tube preamp to drive the music.

I am using a simple copper-coil-inductor on the Alpha-15A's that cuts off frequencies about 175 Hz (I think) in -6 db increments after that.

And a thought... actually an insight flashed into my head: what if I removed the inductor from the Alpha-15A and let it play unfiltered? Before my brain had a chance to inform me that that is entirely wrong... because the Alpha-15A goes up to 2500 Hz thereby overlapping the B200's in the "presence" region... I was taking off the speaker cables from the inductors and joining them.

I sat back in my chair. A powerful blooming sound was coming from my OB's... my brain told me it was wrong... too saturated... too much of a bloom... then my mind relaxed and I managed to push all preconceptions out of my field of attention... and I just listened.

I put on CD after CD... jazz, classical, small scale, large scale, voice: classical and jazz. After about 2 hours I realized that what I was hearing was exactly what the designer I spoke to described what his double-mouth folded-horn speakers are doing.

What I am hearing is incredibly exciting... a fullness of tone that is so rich and palpable... so fleshed out with nuances of tonal shadings... so "present" and "full"... everything sounds alive... it is a continuous "liquid" bloom of sound that infuses itself to your nervous system... it is not polite... it is not "transparent"... it is incredibly full, rich, enveloping. There is more... a great deal of musical information that I thought I was hearing has now appeared in a fuller dimensional "relief"... so that an entire level of music has reintegrated itself into the all-over musical fabric... and voices sound completely "ripe"... Deb and I now hear the singers every breath, even the swallow between stanzas, and the subtle snap of the fingers for example that helps them to enter the rhythm.

And wait until you hear what a piano sounds like without any "filters"... like you are siting right next to it and the overtones are flooding your body... like sea waves splashing your face.

So does it sound like the real thing? Like live unamplified music? Is there such a thing as "sounding like live music"? In what space... how far am I sitting from the musicians?

It sounds deeply engrossing, seductive, emotionally satisfying and even on occasion thrilling!

So why am I tolerating a cross-overless overlapping of the B200's and Alpha-15A's from 175 Hz to 2500 Hz?
Because it sounds quite beautiful, fully-saturated, tonally rich and complex, an incredible bloom of sound that I now find terribly appealing... and Deb loves it as well... it is a "revelation".

So those of you that have the same set-up that I do... or something similar... take a walk on the wild side... take out the copper inductors and resistors and let your 8" and 15" play "full-range" without any filters and see what happens... at the very least you might get a sense of the real potential of Open Baffle design to free your music from the constraints of what we think we know... or have been told to think... and what is actually possible.

Please share your experiences here.

With Warmest Regards ~ Richard

[bassboy]

I don't know anything about you or your system or if you've tried doing any measurements but...

It could be entirely possible that your system measures a bit flatter without the low pass filter.  For example, if you have a massive room induced peak like me (mine is around 60 hz) the midbass (and mids) might seem a bit weak in a speaker that measures flat anechoically.

IIRC the alpha has a massive peak right before it rolls off on the high end, I'll take your word that it's ~2500 hz.  Peaks in the range of 1k - 10khz are pretty common in the different sizes of fullrange drivers that many of us have played with at one time or another, and these peaks are sometimes subjectively described as adding "detail", "presence" and such.  Possibly you like the effect of a peaky mid range.

OTOH, it could be that the big driver and little driver are out of phase and they are working to actually somewhat cancel out this mid peakiness that I just mentioned, in which case you prefer the flatter response due to the beaming cancellation.  (Probably not though since the frequencies they peak at are probably too different)

Either way, it's impossible to know what you are hearing or why you like it.  It's not really important why, the important part is that you like it.  Possibly more important is that your lady friend likes it.

Try taking some general fr measurements from the listening spot both with and without the filter.  That might make things more clear.  IMO flat response will always sound better more of the time on more material than a response with a large fr anomoly.  Exaggerated mids sound great on certain material but very tiring the rest of the time.

[Graham Maynard]

Hi Richard,

I can understand what you are describing. 

I can also understand Bassboy's concern about the Alpha's pre-roll off upper-mid peak which can be reduced by using a Zobel or shallow notch across the driver when a crossover or tube amplifier is being used.

If you were to re-insert your series choke plus a resistor or attenuator in parallel with it you would be able to adjust the blend between choke and direct coupling.

?  I wonder if same baffle mounting with the larger Alpha is sharing displacement and improving reproduction at LF in a manner which reduces the B200 LF displacement, then the increasing B200 efficiency with frequency controls the perception of detail ?

Cheers ........ Graham.

[-Richard-]

During the Middle Ages the collective belief was that the world was flat.

People would look out onto the horizon of the sea and see the tip of a mast... gradually the mast lengthened and the sails came into view... eventually the entire ship rose up from the horizon. The proof that the world was not flat was readily available in that vision which they saw demonstrated everyday. But their "conditioning"... their preconceptions prevented them from actually "registering" what they were seeing.

So it is that the mind... once convinced of something that is deemed "true"... becomes fixated... centered... on that pre-conditioned version of what they think they are seeing... or hearing in this case.

Also... without observation... without direct experience... the mind is prone to endless conceptual probings. Only actual experience will render the facts of what is real and what is imagined. What I am hearing works.

If someone has a similar set-up to mine... or even better... the same set-up... try removing all "filters" from your cables and listen to what happens... I would be most interested.

I have the B200's and Alpha-15A's hooked up in parallel.

Warm Regards ~ Richard

[Graham Maynard]

Hi Richard,

Your amplifier, any pre-amp related EQ and cable connections to the LS drivers must influence reproduction too.
For example whether the Signatures have global NFB and low impedance output;  also whether the drivers are connected together at the baffle and fed by a single cable, or whether each has its own interconnect directly back to the amplifier terminals.

When drivers having different characteristics are connected in parallel on the same baffle, individual resonances become mutually damped by the presence of the other driver.

It is unlikely that I will ever have an opportunity to experience a system the same as yours, but I do still have an interest in understanding what it is about your own which satisfies.  I think it unlikely that its SPL response will keep most folk happy, but then taking the bumps out of a system to make it 'flat' takes out other sounds too.

Cheers ......... Graham.

[FlorianO]

So why am I tolerating a cross-overless overlapping of the B200's and Alpha-15A's from 175 Hz to 2500 Hz?

Because B200 is a bag of shouting sh!t whose beaming masks the cone breakup the cheap-as-cr@p Eminence woof with OTT Qts.

IOW, hi-fi.

Over and out.

[MJK]

Very constructive post Florian, one reason I won't pay much attention to you any more.

I have been thinking about Richard's experiment and results and it might make some sense. The Alpha is not as efficient as the B200 so in his configuration it would tend to augment the rolling off low frequency response of the B200, similar to the Silver Iris + Augie combination. If used as an augmentation driver, and not as a woofer driver responsible for producing all of the low end, it would not necessarily need to be crossed over and the combination might sound better run full range. Working on this concept, there may be room for improvement with a higher crossover point for the Alpha.

[fergs1]

Greetings fellas, Ive wondered the same thing about using the Alpha a lot higher to give a fuller sound. My alphas are on order and I can't wait to play, which is what all this is about. Richard I am very quickly abandoning good design for a far more musical presentation.Sakamura is starting to make a lot of sense to me right now....Its taken a few years but I now implicity trust my own ears as to what pleases them and I know for a fact that a lot of people find my system to rolled off in the top to which I reply I find most systems and modern recordings for that matter too hot in the upper register. Even in the world of diy hifi its down to personal preferences.
                                         good hunting           fergs

ps florian one look at your wall hangings in your stereo room and now I understand

[-Richard-]

Hi MJK ~

"If used as an augmentation driver, and not as a woofer driver responsible for producing all of the low end, it would not necessarily need to be crossed over and the combination might sound better run full range. Working on this concept, there may be room for improvement with a higher crossover point for the Alpha."

Yes... that is my thinking as well... a much higher crossover point... I intend to experiment with a few different very high cross-over points in the near future. I would guess somewhere from 1600 Hz to 2000 Hz. Although, what I am hearing right now is so deeply satisfying that I am in no particular rush to "perfect" it... but I suspect, like you, MJK, that an even better synergy is possible.

The most surprising aspect of the sound, besides the incredibly rich and nuanced tonal pallet... is its sense of a blooming liquid flowing continuousness... perhaps the sound is not quite as dynamic in absolute terms as the "leaner" sound obtained by the more conventional low crossover point that would ordinarily be mandated for "box" speakers... say around 150 Hz to 200 Hz or so. But the sudden appearance of this liquid bloom of rich tonal color and instrumental detail in the "presence" region is so seductive and beguiling that I have no wish to go back to what I now perceive (in comparison) as a somewhat leaner, if perhaps more nimble presentation.

I think you have an excellent sense of what is going on JLM.

Hi fergs ~

"Ive wondered the same thing about using the Alpha a lot higher to give a fuller sound. My alphas are on order and I can't wait to play... Its taken a few years but I now implicitly trust my own ears as to what pleases them and I know for a fact that a lot of people find my system to rolled off in the top to which I reply I find most systems and modern recordings for that matter too hot in the upper register."

I am very interested, fergs, in your experimentation's with the Alpha's, once you have had a chance to incorporate them into your Open Baffles. Please allow them to break-in somewhat... say 100 hours before any "serious" listening. With the B200's they are a remarkably synergistic match... they blend perfectly... and yes... do try them "full range" as well as any "filtering" you may have in mind... and give your assessment some time to gestate... it took a bit of time for me to realize what I was hearing.

It sounds remarkably like a huge folded-horn single-driver speaker that might cost upwards to perhaps $30,000 dollars... you have seen/heard them with their extraordinary wide "mouths" and circuitous passageways.

Using Lloyd Peppard's dual-circuit tube Magic 5 (triode) preamp, I am able to augment the "sound" color somewhat to more perfectly match different recorded material (with Red Wine's Signature 70.2 mono-amps).

"Richard I am very quickly abandoning good design for a far more musical presentation. Sakamura is starting to make a lot of sense to me right now..."

I am not familiar with Sakamura's approach, fergs, can you elaborate on that a bit?

"Its taken a few years but I now implicitly trust my own ears as to what pleases them and I know for a fact that a lot of people find my system to rolled off in the top to which I reply I find most systems and modern recordings for that matter too hot in the upper register."

I have to credit Dan Mason for giving me the full-tilt impetus to experiment with a DIY approach to OB speaker design and learning to trust my own ears... as you point out so well, fergs. And yes... a great deal of "commercial" speaker design is "hot" on top... is "captures" the attention of buyers in audio stores that think they are hearing more "detail" and it sounds as if they are getting "more"... it takes quite a bit of aesthetic maturity to learn how to actually "listen" sensitively. Keep us informed, fergs.

Warmest Regards ~ Richard

[bassboy]

Instead of speculating with increasingly flowery subjective words, why not do a quick measurement of the before and after?

I'm not trying to pick on you, only trying to suggest that if you actually SEE what you are hearing you might understand WHY this alignment is so appealing to you.  As I suggested previously, it's entirely possible that it measures flatter now than it did before.

[fergs1]

Here ya go ,, take a deep breath  and  submerge http://www10.big.or.jp/~dh/codo/index.html  There is also  a cool short film on youtube in Japanese where they tour his restraunt/listening den so look up sakuma (notice I got the name wrong ) and enjoy.
                                                     cheers  fergs

[fergs1]

http://www.youtube.com/watch?v=bbzFsWGYQK4   found it!

                                   cheers  fergs

[-Richard-]

Hi bassboy ~

Finding words to express something as subjective as ones take on a musical experience is not easy... as least for me... so admittedly I do tend to reach for words that I feel carry some of the ephemeral experience of what things sound like... and I am extraordinarily sensitive to what I hear. Most of us are quite content to be as insensitive as we have been trained to be... how else can you explain American's not being outraged by our committing crimes against humanity in an entirely unjust war that has killed over a million people in Iraq.

I have no interest in "measuring" what I am hearing. That is just how I experience things, bassboy... as long as things seem to cohere to some basic fundamental science, I am quite willing to trust what I am hearing as a guide.

That may frustrate some of the readers/posters here on AC, like yourself, who have a legitate interest in understanding what is really going on... quite understandable. That is why I am suggesting that those AC members that have the same set-up as myself experiment with no filters and share their experiences here... perhaps they might be better able to shed some light on the science going on here.

Your prickly tone is not particularly congenial, bassboy... have a bit of patience and the information you are seeking might show up.

Warmest Regards ~ Richard

[scorpion]

Interesting, I wouldn't be too much concernd about the mid- and lower-bass performance but I would certainly be concerned by the steeply rising response of the Alpha-15 up to the 2 kHz point. But then I realised the B200's response. It might well be that these elements, like MJK is argueing, complement each other more than they take themselfs to extremes. If you look at the Visatons published frequency response the Alpha15 might well compliment it up to over 1.5 kHz and then mask  the b200's really 'shouting' passage between 2-3 kHz by providing mellow tones in that range. I don't think for once that it is better sounding because it would really be increasing the overemphasus of these frequencies but in sound it my be mellower. Please remember I was the one suggesting the simple RL-network in the first place in the Gravity thread for simple tuning of the B200 frequency response.

/Erling

[MJK]

The following simulation result shows the SPL response for the B200 and the Alpha 15A both running full range on an assumed baffle. As you cans see the Alpha 15A augments the rolled off bass output of the B200.



The solid red curve is the combined system response at 1 m for a 1 watt input. The dashed red curve is the B200 and the dashed blue curve is the Alpha 15A. I used my standard worksheet OB_Drivers_2_25_08 to run this quick simulation.

My guess is that Richard's baffle produces a similar response and I can see the potential of it becoming a nice set-up. I would still look to roll off the Alpha 15A at some higher frequency to improve the response even more. The other interesting feature is the deep dip at about 1300 Hz, as the listening distance increases from the 1 m shown the dip moves up in frequency into the 2 to 3 kHz range. Maybe the peak in the manufacturer's Alpha 15A SPL response curve is not such a big concern. Looks like a good start with a bit more upside if engineered a little bit further.

Martin

[scorpion]

Martin,

I certainly would not object to your simulation. It would be extremly good if this simulation really could overrule what we hear from our speakers.
Please buy a B200 and listen ! I have seen some independent measurement of the Alpha15, it will have a rising response up to 2 kHz so in that respect I don't think your simulation holds true. But with the Alpha of course you could test its response yourself as I soon will. 

/Erling

[MJK]

Erling,

I think that the simulation is confirming what Richard is hearing if I understood his post correctly.

Remember that the Alpha 15A response curve is calculated off axis and also impacted by the floor response. As far as getting a pair of B200's, I am not sure that is in the cards since I am working on a different design and already have way too many full range drivers.

Martin

[scorpion]

Martin,

Quite sure you have good points and as I have not been able to test the Alpha15s yet you might very well be right. But how do you evaluate Eminence's own published response curve ? As for the B200 there are very different subjective views about their response. I really can't listen to its 1st violin response as it is without liking it to be less agressive ! 

/Erling

[MJK]

But how do you evaluate Eminence's own published response curve ?

Erling,

To be honest, I have not spent much time looking into the higher frequencies of the response curve of the Alpha 15A. I only use them below 200 Hz so it is not such a big concern. I am sure it has some break up behavior at the top end but the resulting response will be very direction dependent. All I as trying to show in the simulation was the use of the Alpha 15A as an augmenting driver and maybe what Richard is experiencing which is different from anything I have ever tried. I would be the first one to recommend rolling the Eminence off at some higher frequency with a high order crossover to try and avoid the break up modes messing with the combined system response. This region of the frequency response curve would need to be carefully designed.

Richard had tried something with his set-up which was promptly dismissed. After thinking a little, I am not so sure it should have been dismissed so quickly. My intent was to set people thinking and looking at what was going on when the crossover was removed. It is not so obvious to me that it cannot work. Listening to the result of an audio experiment is great but I really like to understand why it sounds the way it does to increase my understanding which always leads to other interesting possibilities.

Martin

[scorpion]

Martin,

I agree ! You should not dismiss anything on beforehand because you have a biased view. That's why I also digged up the 'B200. Anyone prepared ...' thread.
I will build stereo Alpha15 H-baffles with two units in each as a result of your study and complementing simulations and possibly these OB-woofers will serve me as my general basspeakers for a long time and to good service. But I wouldn't like yourself let them play much higher than about 300 Hz. Because over there I would have to deal with rising response and resonances. In Richard's flat baffles he won't be plagued by resonances so it might be breakup behaviour that should be a problem. Now that is also subjective if you are blending sounds from more speakers and what unit is dominating.

/Erling